Skeletal isomerization of olefins

ABSTRACT

OLEFINS ARE SKELETALLY ISOMERIZED BY CONTACT WITH A CATALYST COMPRISING A COMPOSITE CONTAINING ALUMINA ASSOCIATED WITH THORIUM OXIDE AND/OR CUPRIC OXIDE WHICH IS SUBJECTED TO FLUORIDE TREATMENT.

' 3,584,070 SKELETAL ISOMERIZATION OF OLEFINS Robert B. Regier,Bartlesville, Okla, assignor to Phillips Petroleum Company No Drawing.Filed Jan. 22, 1970, Ser. No. 5,102

Int. Cl. C07c /22; B01j 11/76 US. Cl. 260-683.2 9 Claims ..ABSTRACTOFIIHE DISCLOSURE Olefins are skeletally isomerized by contact with acatalyst comprising a composite "containing alumina associ-' ated withthorium oxide and/ or cupric oxide which is subjected to fluoridetreatment.

A GRQUND OF. TH MB IIQN Field of the invention This invention relates tocatalytic skeletal isomerization of olefins.

Description ofthe prior art also result in a number of byproducts, bothheavier and lighter than the starting feed material, which seriouslyaffeet the efficiency of the process. Thus, a highly desirable catalyticprocess 'for skeletally isomerizing olefins is one which will provide ahigh degree of selectivity while still retaining the ability to converta larger percentage of the feed olefin per pass. I

OBJECTS OF THE INVENTION It is an object of this invention to skeletallyisomerize olefins with minimum concurrent production of heavier andlighter materials than the feed olefin. It is a further object of theinvention to selectively skeletally isomerize olefins at highconversions per pass over the catalyst. Other objects and advantages ofthe present invention will be apparent upon readily the detaileddescription of the invention, the example, and the claims.

SUMMARY OF THE INVENTION I have discovered that olefins can beskeletally isomerized by contact with a fluorided catalyst compositecomprising alumina promoted by T110 and/ or CuO.

DETAILED DESCRIPTION OF THE INVENTION The presence of the T110 and/orCuO in thecatalyst composite of the invention increases the skeletalisomerization selectivity when compared with fluoride alumina alone. Thealumina-containing composite of the present invention isone whichcontains amajor amount by thorium oxide and/or cupric oxide. Othermaterials which 'do not adversely effect the catalyst activity andselectivity can be present in the catalyst composition as long as the 7Patented June 8, 1971 alumina component comprises at least 50% by weightof the composite. Preferably, the composite contains from about 5 toabout 25 weight percent of ThO and/ or CuO promoter material. Suchcatalystic compositions are known in the art and generally commerciallyavailable. They can be prepared by any suitable means such as bycoprecipitation, impregnation, or dry mixing.

The catalyst composite requires relatively little preactivation beforethe fluoriding treatment. Because steam is evolved in the fluoridingtreatment, it. isunnecessary ,to go to great lengths to dry the catalystcomposite prior to the fluoriding. Thus, preliminary drying of thecomposite at temperatures of up to about 200 C. or higher, if desired,is sufficient.

The fluoriding of the above-described composite can be carried outeither in liquid phase or in' vapor phase at a temperature of at leastabout C. In a liquid phase treatment, a suitable procedure is to heatthe composite with an aqueous solution of either hydrofluoric acid orammonium fluoride for a time which is sufiicient to add a substantialamount of fluoride to the composite and to improve the catalyticelfectiveness of the composite. In vapor phase fluoriding, which is thepreferred method, a suitable procedure is to contact a bed of thecomposite with hydrogen fluoride at a bed temperature of at least 100 C.but not exceeding about 400 C. Steam will be evolved throughout thefluoriding operation and the fluoriding will be considered completewhen, at a given set of fluoriding conditions, copious amounts ofhydrogen fluoride are observed leaving the bed. It has been found thatthe extent of fluoriding will depend upon the temperature of thecatalyst bed. Thus, even after hydrogen fluoride is observed to bepassing through the bed without further reaction at a specific bedtemperature, additional fluorine can be added by allowing a furtherincrease in the bed temperature.

The fluoriding operation is highly exothermic and, for purposes ofcontrolling the temperature, the hydrogen fluoride preferably should bediluted with an inert gas such as nitrogen, or a noble gas such as argonand the like.

The hydrogen fluoride can be a minor portion of the treating gas butshould comprise at least about one volume percent of that gas. After thefluoriding treatment, the treated catalyst composite should be flushedwith an inert gas to remove unreacted hydrogen fluoride or any othervolatile materials. The flushing should take place at a temperaturewhich is at least the temperature of the subsequent conversion reactionand can conveniently be as high as about 550 C. or higher.

The olefins to which the invention is applicable are those olefiniccompounds which can undergo skeletal isomerization. Preferably,skeletally isomerizable olefins which have from 5 to about 12 carbonatoms per molecule are employed. Monoolefin hydrocarbons are morepreferred and these can be terminal or internal, and branched orunbranched. However, it is preferred that branching, if present, be atleast one carbon atom removed from the double bond. Suitable olefinsinclude pentene-l, pentene-2, hexene-3, 4-methy1octene-l, decene-2,3-methyldecene-l, 3-dodecene, and the like, and mixtures thereof. Theinvention also contemplates the skeletal isomerization ofolefincontaining streams such as those found in the production [ofdistillation fuels, e.g., gasoline.

According to the process of the invention, the feed described catalystsystem at a temperature in the range The C components were furtheranalyzed and were found of from about 300 to about 600 C., preferablyabout to consist ofi 310 to about 525 C. and at any convenient pressurein I so entane 0.7

the range of the from about to about 2000 p.s.1-g., rela- 3ngethylbutene l 2.2 tively low pressures being preferable. Any suitabletype nyentane 03 of contacting technique can be used, a continuousprocess 1 pentene 9.7 using a fixed catalyst bed being particularlyconvenient. 2 methylbuten 1 13.7 Using such a fixed bed operation, thefeed will be ad- Trans pentene 2 2&4 mitted at a weight hourly spacevelocity in the range of cis pentene z 15.9 from about 0.1 to about 10,preferably 0.5-5. After con- 0 29 2 methylbutene 2 .0 vers1on, theproduct can be separated and/or lsolated from the reactionmlxture by anysultable means. Uncon- Thus, the conversion f pentene 2 n the was 47verted feed materral can be recycled to the reaction zone. and theselectivity to isopentenes was The invention is illustrated by thefollowing example. The essential data from this run and other runswithHowever, it is understood that the data of the example is 15 othercatalysts, including several comparison runs with provided for thepurpose of illustration and should not be fluorided alumina, are shownin the table below.

TABLE.SKELETAL ISOME RIZATION OF PENTENE-2 Fluorided 90-AlzOa/10Th0zFluon e A1203 catalyst catalyst Fluorided 90-Al2Oa/10-C U0 catalystRegen- Fresh Regenerated Fresh erated Fresh Regenerated Run N0. 1 2 3 45 6 7 s 9 10 11 12 13 14 15 16 17 18 19 29 Temperature, o 316 346 391312 342 284 423 454 365 413 462 511 415 613 313 365 414 369 408 460Conversion, percent 26.8 35.5 48.1 25.6 31.7 45.3 56.6 60.6 23.5 35.044.0 46.5 84.0 47.1 22.1 38.5 5 .0 27.7 47.9 61.6 Selectivity, percent81.4 83.2 80.9 80.5 84.3 82.0 81.8 80.5 92.4 92.6 92.3 92.2 92.4 93.092.7 90.6 87.3 93.5 90.6 84.6

construed as limiting the scope of the invention as above 30 1 Thesedata illustrate the improvement obtained by described. using, as askeletal isomerization catalyst, a fluorided Example alumina which hasbeen promoted with minor amounts of CuO or ThO prior to the fluoridingtreatment. It is read- Thfl PmcfisS of the Present invention Wasdemonstrated ily seen that the invention process results in much higherin a number of runs in which pentene-Z was skele ally S0- selectivitiesover a broad range of conversion levels than merized in a fixed bedcontinuous reaction over several the process using fluorided butunpromoted alumina. catalysts and at different temperatures. Each runwas car- Reasonable variation and modifications of my invention ried outat atmospheric pressure and at a weight hourly are possible withoutdeparting from the spirit and scope space velocity of 2-3. thereof.

Each of the catalysts used was a commercially avail- 4 I claim: blcatalytic grade composition in the form of A; inch 1. A process ofskeletal isomerization'of olefins which pellets. Before undergoing thefiuoriding treatment, each Comprises Contacting a ee olefin with acatalyst comcatalyst composition was dried at about 200 C.Followprisillg a fluorided Com-posit6 of at least 50 Weight P61?cent ingthe drying, a fixed bed of the catalyst was treated with alumma Promotedy an oxidi Selected from the group consisting of copper and thorium. a

2. A process according to claim 1 wherein the catalyst contains fromabout 5 to about 25 weight percent of cupric oxide or thorium oxide.

a flowing equimolar mixture of nitrogen and hydrogen fluoride gas at arate such that the maximum temperature of the bed did not exceed about200 C. The treatment was continued in each case until copious amounts ofHF 3. A process according to claim 1 w e t e feed 01ewere observed atthe exit of the catalyst bed. The flow of fin 1s contat d th- 7 HF wasthen cut oil and the bed was flushed with mtrogen range of 8 33 23 8., gg g i i ecrature m the while the bed temperature was elevated to about500 C. A process according to claim 3 wherein the feed Ten m1. of eachreated Catalyst Was then chargfid as fin has 5 to 12 carbon atoms permolecule and is capable fixed bed into a glass tubular reactor throughWl'llCh the f being Skeletahy isomerizedpentene-2 was passed underreaction conditions. The re- 5. A process according to claim 4 whereinthe feed oleactor efiluent was passed into a 0 C. condenser and fin is aterminal or internal, branched or unbranched collected. Only anegligible amount of gas was not remonoolefin hydrocarbon. 1 covered bythe condenser. 6. A process according to claim 1' wherein the aluminaThe reactor efiluent from about 50 minutes of opera- Promoted y an oxideof pp thorium has been tion was obtained for each run. This was thenanalyzed fluoride? with a11 aq1160l1S S01l1ti0n'0f y fl ri ac d r bygas-liquid chromatography. The catalyst beds were reiggg g fluorlde at atemperature f at ast a ut generated by a passage of flowing air at a bedtemperature of about 500 C. until any carbon present in the bed had beenburned off.

In one run, a regenerated fluorided Al O 10ThO 5 7. A process accordingto claim 1 wherein the alumina promoted by an oxide of copper orthoriumhas'been fiuorrded with gaseous hydrogen fluoride in the presenceof an inert gas diluent at a temperature of at least about has useziatorgmvegt pentene-2 at a reactor temperature of 6 C 20 out 5 T e reactorefiluent, excluding negligible amounts of light and heavy ends, wasanalyzed and ffi ggiigi egclcordmg to claim 5 wherein the monofound tocons1st of: 7O 9. A catalyst consisting essentially of at least 50weight Weight percent percent alumina promoted by from about 5 to about25 C 0,2 Weight percent of an oxide selected from the group con- 0 1,0SlSting of copper and thorium which has been subjected C 97 7 totreatment with hydrogen fluoride,

C 1-1 75 (References on following page) 6 References Cited 3,426,089 2/19 69 DeRosset 252442 3,432,562 3/ 1969 Gardner 252442 UNITED STATESPATENTS 3,505,417 4/1970 Gardner 252442 8/1959 Heinnemarm et a1.260-6832 3,457,189 7/1969 De Rosset 252442 6/1944 Thomas et a1 260-6 325 3,514,253 5/1970 Robota 252442 5/1944 Day et a1. 260-6832 /1943 Thieleet 1 2 5 33 2 DELBERT E. GANTZ, Primary Examiner 5/1949 Oblad et V.OKEEFE, Assistant Examiner 11/1965 Moore et a1. 260-6832 12/1966 VeCChiOet a1. 252442 10 US. Cl. X.R. 11/1968 Gardner 252442 252442

